Various types of information recording media, such as a digital versatile disc (DVD), a Blu-ray (registered trademark) disc (BD), a flash memory, have been used as information recording media (media) on which various types of content, such as a movie and music, are recorded. In general, for example, the creator or the distributor of content, such as music data or image data, recorded on the information recording media has a copyright or a distribution right to the content. Therefore, the user who has purchased the disk also has limits in the use of content recorded on the disk. For example, the unrestricted copy of the content recorded on the disk to other media is not permitted.
As a copy management configuration for the content stored in a medium, there is a configuration in which copy is permitted on condition that copy management information is received from a management server.
Specifically, for example, a process is performed in the following sequence.
A user inserts a first medium which is a copy source, such as a content-stored disk, into a user device, such as a PC or a recording/reproducing device, and the user device is connected to the management server through a network. Then, the user device transmits predetermined information, such as a disk identifier (ID) of the first medium, to the server.
The server checks, for example, the validity of the received information and transmits copy management information in which, for example, copy permission data has been recorded to the user device. The user device can check the copy permission data recorded in the copy management information transmitted from the server, read out the copy permission data from the first medium, and copy the copy permission data to the second medium which is a copy destination.
The copy management configuration is referred to as managed copy (MC) and has been described in detail in, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-98765).
In a case where the user device copies content stored in a medium, such as a Blu-ray (registered trademark) disc (BD) storing, for example, a movie which is a copyright management target, to another medium, such as a flash memory, or another medium, such as another disk, the user device needs to perform a process according to the managed copy (MC). That is, copy is permitted on condition that copy management information is received from the management server.
In general, much of content, such as a movie, recorded on a general content-recorded disk, such as a Blu-ray (registered trademark) disc (BD), is encrypted and recorded in order to prevent illegal use such as an illegal copy.
Content encrypted according to an advanced access content system (AACS) standard which is a standard related to a content copyright protection technique is recorded as encrypted data which is divided into units and in which different encryption keys are applied to the units. The configuration in which each unit is encrypted makes it possible to perform usage control for each unit and various kinds of content usage control are strictly implemented.
However, the current AACS standard is mainly a standard for usage control for content that has been recorded on a Blu-ray (registered trademark) disc (BD) in advance and has the problem that copy content usage control needs to be improved in a case where content recorded on the BD is copied to another medium and is then used.